PORTLAND, Ore. — Police searching for a 15-year-old runaway girl found two bodies Wednesday off a trail in a forested park in Portland but said they could not release the identities of the dead until autopsies were complete.

The gruesome discovery came during the second week of an extensive search for Annieka Vaughan, an Aloha teenager who authorities say ran away with Zachary Petersen on Oct. 30. Petersen, 23, was under investigation for sex abuse in a Washington state case that named Vaughan as the alleged victim, said Portland police Sgt. Chris Burley.

Petersen, of Pasco, Washington, called a crisis hotline before vanishing on the same day Annieka ran away, authorities have said. He was believed to be armed and suicidal.

The unidentified bodies were found by a cadaver-sniffing search dog tucked behind a tree stump about 80 feet off a trail in Forest Park, said Detective Robert Rookhuyzen of the Washington County Sheriff’s Department. Petersen’s abandoned white pickup truck was found Monday in a nearby gravel lot and Annieka’s backpack was inside.

The location of the bodies is about a 10-minute walk from that parking lot, Rookuyzen said.

“We notified the family members of the discovery of these bodies just in case it’s them,” he said. “The bodies have been removed from the scene but the scene is still being worked for evidence. … The biggest thing here is to get them identified.”

Authorities have been searching the park exhaustively since the truck was found and credited the search dog for the discovery. They also found a backpack at the scene.

“They would not be seen from one of the many trails. They would not likely have been found without this dog,” said Burley.

Autopsies will take several days because of a backlog at the Oregon State Medical Examiner’s Office due to a number of traffic fatalities, he said.